L2900 - Glow Plugs Short Runtime - Bad Controller?

[Clutch]

Good evening everyone.

I went to start my L2900 last week when the temps outside were in the low 40s(F). When I went to start, the glow plug light on the dash only stayed lit for about a second before it went out. This was definitely odd, since I have had it stay on for several seconds when it was warm out. I repeated the cycle a few times and it fired right up, but would like it if they would just stay on for a full cycle.

Does it seem like this is probably a bad glow plug controller?

From looking at the photos online they are manufactured by NGK, but I cannot seem to find them on the NGK website. I see some listed on Amazon or eBay but am leery of fakes there.

Appreciate any thoughts/help here.

 

[PoTreeBoy]

Good evening everyone.

I went to start my L2900 last week when the temps outside were in the low 40s(F). When I went to start, the glow plug light on the dash only stayed lit for about a second before it went out. This was definitely odd, since I have had it stay on for several seconds when it was warm out. I repeated the cycle a few times and it fired right up, but would like it if they would just stay on for a full cycle.

Does it seem like this is probably a bad glow plug controller?

From looking at the photos online they are manufactured by NGK, but I cannot seem to find them on the NGK website. I see some listed on Amazon or eBay but am leery of fakes there.

Appreciate any thoughts/help here.

I don't have access to the WSM for your L2900, but it appears to use the same glow controller as my L35. So I'm assuming it uses the same logic system. If so, there is a separate thermo sensor, similar to the temperature gauge sensor, that varies the preheat time depending on coolant temperature. If there is a short to ground in the sensor or the wire between it and the controller, the controller would assume hot coolant and shorten the preheat time.

When my controller failed, it would turn the plugs on at random times while the engine was running. I bought a controller on eBay for about 1/4 Kubota's price and it's been working for several years.

 

[GreensvilleJay]

What PTB says makes a lot of sense ! The 'controller IS 'controlling', just wrongly thinks the engine is hot or up to 'operating temperature'
easy ? test, remove wire at the sensor, see how the controller reacts.

 

[ruger1980]

You really need to have the logic for the control of the plugs to determine if this is normal or not. All of the Kubota built engines which we put in our machines seem to cycle the glow plugs for about 1 second until until coolant temp is below 32F. Then cycle time increases increases with a decrease in temp. This "ramp" is not that steep and may be progressive. I have had customer complain thinking the glow plugs should cycle longer but if the engine starts the system is generally functioning properly.

I will see if I can find some of the control figures tomorrow when I am back in my work computer.

 

[Clutch]

Thanks everyone.

I have an electronic version of the WSM somewhere around here. I'll have to see if I can find time to dig it out and do some looking. Appreciate the input so far!